Process for preparing melanin pigments by bioconversion and use of the pigments obtained in cosmetics

Abstract

PCT No. PCT/FR93/01138 Sec. 371 Date Jul. 18, 1994 Sec. 102(e) Date Jul. 18, 1994 PCT Filed Nov. 19, 1993 PCT Pub. No. WO94/12653 PCT Pub. Date Jun. 9, 1994The present invention relates to a method for the preparation of a melanic pigment by enzymatic bioconversion, implementing a melanin precursor substrate and plant cells, characterized in that: (a) poppy (Papaver somniferum) plant cells previously cultivated are separated from their culture medium and subcultured in a culture medium with a concentration from 10 to 100 g/l; (b) the cells are ground at least partially, before or at the end of the latency time, (c) the at least partially ground cells are placed in a bioconversion medium in the presence with a melanin precursor substrate selected amoung indol, indolin, dihydroxyphenylalanin, tyramin and tyrosin; (d) the precipitated melanic pigment is collected. The invention also relates to the utilization of such resulting pigments for the preparation of cosmetic compositions.

We claim: 
     
       1. Process for preparing a melanin pigment by enzymatic bioconversion, employing a melanin precursor substrate and plant cells, comprising: a) separating poppy (Papaver somniferum) plant cells previously cultured from their culture medium and subculturing the separated poppy plant cells in a culture medium at a concentration ranging from 10 to 100 g/l,   b) at least partially grinding the cells before or at the end of the latency time,   c) bringing the at least partially ground cells into contact, in a bioconversion medium, with a melanin precursor substrate selected from the group consisting of indole, indoline, dihydroxyphenylalanine, tyramine and tyrosine, and   d) recovering precipitated melanin pigment.   
     
     
       2. Process according to claim 1, wherein the culture medium in which the previously cultured cells are subcultured has a concentration of between 20 and 50 g/l. 
     
     
       3. Process according to claim 1, wherein the substrate is brought into contact with a ground cell preparation. 
     
     
       4. Process according to claim 3, wherein the ground cell preparation is obtained by grinding the cells, previously separated from their culture medium, at a temperature of between 0° and 15° C. 
     
     
       5. Process according to one of claim 1, wherein the contacting of the at least partially ground cells with the substrate is carried out with stirring. 
     
     
       6. Process according to claim 1, wherein the contacting of the at least partially ground cells with the substrate takes place at a temperature of between 10° and 70° C. 
     
     
       7. Process according to claim 1, wherein the contacting of said cells with said substrate is carried out in a buffered solution having a pH between 3 and 9. 
     
     
       8. Process according to claim 1, wherein the precipitated pigment is recovered by filtration, decantation or centrifugation. 
     
     
       9. Process according to claim 8, wherein the precipitated pigment is recovered by filtration of the bioconversion medium through a screen of mesh size less than 5 μm.